This invention is directed to a circuit for preventing chatter in a switch having a mechanical contact, and in particular to an input chattering preventive circuit particularly adapted for use in miniature portable equipment.
It has been recognized that a switch having a mechanical contact invites chattering thereof while being used. Accordingly, circuits have been developed to suppress chattering before the signal produced by the switch is used as an input. For example, an electronic circuit for eliminating chatter from a contact signal is disclosed in U.S. Pat. No. 4,057,738. Another anti-chatter circuit for use in a small portable apparatus is disclosed in my co-pending U.S. patent application Ser. No. 06/277,293, filed June 25, 1981, now U.S. Pat. No. 4,417,155. Although such circuits act to substantially eliminate chatter, an improved chattering preventive circuit for use in miniature portable equipment such as calculators and watches which effectively eliminates chatter is desired.